1. Field of the Invention
This invention relates generally to pressure sensing devices and, more particularly to devices for sensing pressure that are comprised of passive integrated circuit elements fabricated on a single crystal.
2. Discussion of the Related Art
It is known in the related art that deformation of an integrated circuit type of resistive element can cause a change in the value of the resistance, generally referred to as a piezo-resistive effect. Typically resistive elements are formed on deformable sections of a material and the variations in the resistance can be used to determine the force applied to the material.
These devices, as implemented in the past, have several disadvantages that have limited their usefulness. In particular, although the piezo-resistive elements are formed on the deformable material, the associated elements are typically comprised of discrete components and are located in a separate circuit area. To increase sensitivity and accuracy, the piezo-resistive elements are typically components of a bridge circuit, requiring several associated circuit elements. The use of discrete elements is not an effective use of space. In addition, the resistive elements are temperature dependent and, for accurate pressure measurements, temperature compensation is required.
A need was therefore felt for a component that includes, not only the piezo-resistive elements, but the associated circuit elements as well. A further requirement for the component is the use of passive circuit elements and the inclusion of temperature compensation in the component.